Mardi Ford
Staff Writer
Yes, spring is definitely in the air the birds and bees,the bacteria and viruses, the flies and mosquitoes.
Believe it or not, those nasty insects are already on the fly innocuously doing their best to spread as much sickness as they can.
Which means horse owners should be on the alert for signs of two diseases in particular, West Nile virus and pigeon fever also known as pigeon breast, dryland fever and dryland distemper.
State Veterinarian Don Hansen is again calling for horse owners to vaccinate for West Nile (see related story), which can be potentially fatal to the horse. Public health concerns associated with the West Nile virus, it has been reported in humans as well, make its reporting mandatory to the state, Dr. Hansen says.
However, local veterinarian Dr. Jeff Henry says having an available vaccine for West Nile makes it manageable.
"Get your horse vaccinated," he says simply. "And if you already did it last fall, get a booster. Then you're covered."
Pigeon fever is another story.
Elusive and unpredictable, pigeon fever is a bacterial infection most horse owners have never seen, even if they've heard of it. For years, it was known as California's horse problem, but slowly spread into Colorado, Wyoming and other western states including Oregon.
Last fall, it showed up in Union County.
"Pigeon fever has been around for a long time, but it comes and goes," says Dr. Hansen. "It's caused by a bacteria (Corynebacterium pseudotuberculosis), and it is more common in sheep and goats almost chronic. The best information says it's spread by insect bites."
Hansen says the bacteria needs an entry point a break in skin or even mucous membranes will do if no insects are in season. It can live in the soil, feed, bedding and manure for as long as two months.
Hansen says the pus from draining abscesses carry the bacteria and should be treated as bio security. It can be hard to get rid of and spreads easily if not dealt with properly.
"It can be spread through using common tools, gloves, pails anything that comes in contact with the horse. Best bet is to quarantine the horse and be careful handling the infected horse. Even if you get some on your sleeve and then groom another horse, you take the chance of passing it through a break in the skin," Hansen says.
Deep abscesses often occur in the chest area, which causes painful swelling of the pectoral muscles hence the name of pigeon fever.
The infection manifests in one of three ways:external abscesses, internal abscesses and limb infection, also known as ulcerative lymphangitis.
Recovery can be as quick as a few weeks to as long as a few months. Abscesses may cause multiple sores along the chest, midline and groin area and, sometimes, the back. The incubation period before symptoms show up can be a matter of a few weeks.
Symptoms include lameness, fever, depression, weight loss and swelling which, initially, indicate many other diseases. Sometimes the only sign your horse is infected is a reluctance to move, because it hurts to do so.
A good anti-inflammatory like Phenylbutazone will give the horse some comfort, but Dr. Henry cautions against using antibiotics before checking with your veterinarian. Abscesses may internalize if treated prematurely by injected antibiotics.
Dr. Henry suggests an ultrasound to find where, how many and how deep abscesses are and if they can be aspirated by needle.
"Some (abscesses) are too deep and need to come to the surface. Heated, moist compresses are the best way to get them to do that. And they provide the horse with some relief, too," Henry says.
Pigeon fever is not transferrable to humans, which makes it hard to document. It impossible to say how many cases of pigeon fever have occurred in Oregon recently, but it certainly is on the rise.
"I've been here since 1993, and this was the first year we've seen any here." Henry says.
"Last summer, early fall we were seeing sometimes two to three cases a day. Then around Thanksgiving, they stopped. Now they're back again," Henry says.
Dr. Henry says it seems to have come back again in the same horses it showed up in last fall.
"Nobody really understands (pigeon fever) some years its more prevalent than others. It can show up in one horse out of a herd and not in another one. Why this year? I don't know. There's no rhyme or reason to it."
Dr. Henry does suggest preventative measures such as fly spray and masks, for keeping down the insect population. Dr. Hansen concurs.
"Anything you can do to keep the flies and mosquitos down around your animals is a good idea. Keep the manure in stalls picked up and drain standing water, too."
